Stonecutting apparatus and method using saw and water jet

ABSTRACT

An apparatus for cutting stone which utilizes both a circular saw and a water jet. Both the saw and the water jet are mounted on a gantry, which moves along tracks. All the parts are under the control of the CNC device. The saw is used for straight cuts and curves where possible. The water jet, which is slower and more expensive to operate is only used where the saw cannot be used. The water jet is used to finish a saw cut to avoid any overtravel.

This Nonprovisional application claims priority under 35 U.S.C. § 119(e) on U.S. Provisional Application No. 60/602,862 filed on Aug. 20, 2004, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates generally to a cutting method and apparatus to cut stone and similar material and more particularly to a stone cutting method and apparatus utilizing both a traditional saw and a water jet machine.

DISCUSSION OF THE BACKGROUND

Stone is often cut in order to be used for countertops and other applications such as floors or building facades. The stone may be natural stone or synthetic stone. This is a difficult and expensive procedure. For countertops, the slabs often average 5 by 10 feet and 2-3 centimeters thick, although varieties of sizes and thicknesses are used. Thus, the slabs from which the finished products are made are large, heavy, and difficult to handle.

Currently, in order to make a stone countertop, one workman goes to a job site to make a template. Since building walls are not perfectly square or straight and cabinets on which the countertop is placed are not always aligned with the original plan, the template recreates the irregularities so that the countertop can be fit properly. The hope is that the countertop can then be used without modification on the job site. The template is brought back to the manufacturing shop where the shape is traced onto a stone slab. Parts are then cut from the raw slab using circular saws. These may be either hand held saws or large power-driven circular saws under manual control.

As shown in FIG. 1, when a circular saw is used to cut a desired part 12 from a stone slab 10, cuts 14 are made within the slab to separate the desired part from the slab. However, in order for the circular profile of the blade to pass through the entire thickness of the material, an overtravel section 16 occurs. This overtravel causes excess material to be used and has the potential to damage adjacent pieces that are also being cut from the stone nearby.

To prevent damaging adjacent parts, the slabs are cut in a specific sequence and the parts are removed from the table in order to prevent damage to the cut part while subsequent parts are being cut. Many of the parts require more than a single person to lift them out of the way before cutting can continue. The excess handling requires additional manpower and time to process the job. After the slab is cut into several pieces, they can be individually replaced on the saw for final material removal on any remaining edges that were not cut prior to the removal of the part.

After the individual parts are rough-cut from the slab, they will be moved to other machines to shave and polish the edges. Pieces can then be assembled into the final countertops either in the shop or more commonly during installation in the field.

The current operation requires the use of excess material due to the overtravel section of the saw. There is also a danger of accidentally cutting other parts, which are being cut from the same slab. Further, the process requires that a template be formed manually, which is transcribed to the slab.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a cutting apparatus which avoids the problems of overtravel of the saw.

The present invention further provides a cutting apparatus, which eliminates wasted material in the cutting operation.

The present invention also provides a cutting apparatus, which avoids damage to neighboring parts being cut from a slab.

The present invention further provides a cutting apparatus which utilizes a computer numerical control operation and can accept an electronic template for laying out parts to be cut on the slab.

The present invention further provides a cutting apparatus using a combination of a saw and a water jet machine.

The present invention still further provides a cutting apparatus using a saw and water jet machine under the control of a computer numerical device.

The present invention also provides a cutting method where a saw and water jet are moved under control of a computer numerical device.

The present invention still further provides a cutting machine for cutting stone materials utilizing both a saw and a water jet machine under a computer numerical control operation in order to avoid overtravel of the saw and wasted material.

This is achieved by the present invention by providing a cutting apparatus with a saw for cutting straight cuts and a water jet machine for finishing straight cuts and performing curved cuts. The result is that no overtravel is performed, which removes any possibility of damaging additional parts or wasting material.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a top view of a stone slab being cut by a traditional method;

FIG. 2 a is a front view of the apparatus of the present invention;

FIG. 2 b is a top view of the apparatus of the present invention;

FIG. 2 c is a sectional view of the residue tank used in the present invention; and

FIG. 3 is a flow chart showing the steps of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, wherein like reference characters designate identical or corresponding parts throughout the several views, and more particularly in FIG. 2 a, where a front view of the present apparatus 20 is shown. The cutting apparatus includes a saw 22 and a water jet machine 24 both mounted on a traveling gantry 26. The gantry is mounted on tracks 28 which extend along the length of the apparatus. The traveling gantry extends perpendicularly to the tracks and is movable in the longitudinal direction of the tracks.

A residue tank 30 is placed below the gantry and is used to collect the water and residue from the cutting operations. The top of the tank is a support grating 32 on which the stone slab or other workpiece is placed. The support grating has multiple holes through which the water and other residue can travel. The lower portion 34 of the tank merely acts as a container for receiving and storing the water and residue, which travels through the grating.

The grating 30 is designed to support the work piece and thus must be made from a strong material. However, it is relatively porous so that it permits water from the water jet and any debris to pass there-through into the lower section 34. In addition, the grating must be non-aggressive to the saw blade. The tank dissipates the water jet after it comes through the work piece and also collects the debris from the cutting process.

The saw 22 is a traditional circular saw and can be similar to the one used in the traditional arrangement described in regard to FIG. 1. However, the saw is mounted for movement along the gantry. In addition, the saw may be moved up and down. It also may rotate about its vertical so that the cut may be performed in any direction. Since the gantry can also move along the length of the slab, the saw has 4 axes along which it may be adjusted in order to cut in the desired position.

Water jet 24 is also mounted on the same gantry as the saw. The jet can move along the gantry and can also move up and down to place it near the stone slab. Since the gantry also moves along the length of the slab, the water jet has 3 axes of movement.

While either the saw or the water jet can be used to make any cut, in general the saw is faster and less expensive to operate and accordingly is used wherever possible. The water jet operates at a slower rate but is able to make curved cuts and does require an overtravel to complete a cut. Thus, the saw may have feed speeds in the range of 72-120 inches/minute for a 2-3 centimeter thick stone slab. The water jet for a similar material may have a rate of only 10-15 inches/minute. Generally, the saw will be used for straight cuts and for some simple outside radius curves. The water jet is used for inside radiuses and tighter outside radiuses. It is also used to cut the end of straight cuts in order to avoid the overtravel of the saw.

All of the movements of the saw, water jet, and gantry are performed under the control of a computer numerical control device (CNC) 40, which is connected electronically to cutting apparatus 20. The CNC device can store electronically patterns of parts which are desired to be cut and can control the movement of the saw, water jet, and gantry and the various axes and orientations as desired. In addition, the CNC can be used with various types of available software in order to lay out the various parts. In addition, the CNC can determine the appropriate use of the saw and water jet in order to maximize the speed of the apparatus.

In addition to controlling the movement of the saw and water jet, the software in the CNC can also control the water pump operation and abrasive feed rate so as to cut the material with a minimum run time and in order to minimize cycle time, pump operating time, and the amount of consumables used. For cutting hard material like granite, the water jet machine uses a relatively expensive abrasive compound that is added to a stream of water to accelerate the erosion process of the water jet on the work piece. In addition, the ultra-high pressure water pumps required for the cutting process require frequent replacement of seals and jet valves. With careful management of the water jet tool by the software, the relatively high cost of operation is minimized and the use of the tool becomes more effective in a cost-sensitive manner.

As indicated above, even on straight cuts the water jet is used to finish the uncut portion at the end of the cut. An additional advantage to this arrangement is that the saw blade tends to push on the work piece while it is cutting. As the slab is being cut into smaller pieces, it has a tendency to move due to the force of the saw, which can damage the part as it separates from the surrounding material. By utilizing the water jet to finish the straight cuts, the parts are not moved, the overtravel is removed and the possibility of damage is also removed. When the saw is being used in a straight cut, an end material, referred to as a tab, is left uncut at the end of each saw cut, which is later removed by the water jet. An additional advantage of this arrangement is that it is not necessary to hold the part in place with clamps since the water jet cuts the tabs without any lateral forces and thus the parts are not shifted out of alignment during the cutting operation.

The use of the CNC also simplifies the operation of the apparatus. First, it allows the use of electronic templates rather than physical templates. Thus, the workman in the field can forward the dimensions by email, internet, or direct phone transfer so that the electronic template is set up in the CNC for each necessary part. Such a template can be more precise than a physical template, especially since the physical templates are often created out of scrap material or cardboard. The CNC is then able to arrange the parts on the slab electronically before beginning cutting. This often provides for a saving in material and eliminates a costly manual layout operation. When the cutting operation is finished, the CNC can still be used to control other machines such as a router or other type of edge polisher. The CNC also controls the use of the saw and water jet so that the maximum efficiency is obtained. The saw is used for straight cuts and curves with a relatively large outside radius. The water jet is used for other cuts. It is also used to remove the tabs at the end of each saw cut. The water jet can also be used to cut any remaining areas so the individual parts do not have to be removed until they are all cut without any damage to any of the parts.

Both the saw and the water jet are independently controlled by the CNC using software that is specific to that machine. The CNC dictates the start and end points of the cuts of each tool so as to optimize the use of the apparatus. The software determines the point at which the cut stops or turns and stops the saw before the endpoint or the beginning of the curve. The CNC directs the water jet to finish the cut in these areas during its part of the operation. The software within the CNC is able to determine the appropriate end points and turning points and also determines when the amount of curvature is too great for the saw. A standard commercially available computer aided manufacturing CAM software package can be utilized to generate the part model or models, which are being cut out of the stone. The model files are then processed to generate G-codes and M-codes, which are machine instructions to move and operate the cutting tools. For multiple cuts, the parts can be nested together with the goal of getting the greatest number of parts out of the slab.

FIG. 3 is a flow chart showing the machine control function of the CNC. In step 50, the geometry of the various parts is entered electronically so that the CNC can determine the best layout of the parts on the slab. In step 52, the slab is loaded onto the grating and aligned as necessary. In step 54, the CNC determines the G-codes for the saw and water jet. The saw is then moved to its starting point, turns on, and is lowered in order to start the cut. Near the end of the cut, the saw is slowed and raised and then moved to the next cut.

In step 56, the next cut is started by lowering the saw, cutting and then slowly feeding near the end of the cut before raising it. In step 58, it is determined if any further cuts are needed by the saw. If the end of the saw cutting does not occur, the process returns to step 56 to proceed with the next cut. This will continue until all of the saw cuts have been completed.

At this time, the process continues from the “Yes” answer of step 58 to step 60 to begin the use of the water jet. The various G-codes are produced for the water jet, the pump is started, and the water jet proceeds to the location of the first cut. The water jet abrasives are begun in order to cut the material and then stopped when the end of that cut is reached. The process continues in step 62 to go to the next saw cut and proceed in the same manner. In step 64, it is determined whether the cutting has ending. If not, the process returns to step 62 and additional cuts proceed. When the cutting is ended, the process proceeds to step 66, where the pump is stopped and the water jet is returned to its starting position. In step 68, the parts that were cut can now be removed from the grating.

Although not shown, various motors are included for moving the saw, the water jet, and the gantry along their respective paths. The motors are under the control of the CNC and operate in a known manner. Other modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise as it has been specifically described herein. 

1. An apparatus for cutting hard material, comprising: a saw; a water jet; a support for holding and independently moving said saw and said water jet; a control for separately controlling movement of said saw and said water jet.
 2. The apparatus according to claim 1, wherein said control is a CNC control.
 3. The apparatus according to claim 1, wherein the saw is a fully articulating circular saw.
 4. The apparatus according to claim 1, wherein the support is a traveling gantry on which said water jet and said saw are mounted, said water jet and said saw moving along the longitudinal direction of the gantry; said gantry being mounted on fixed tracks with said gantry moving along said tracks and transverse to the longitudinal direction of the gantry.
 5. The apparatus according to claim 1, further comprising a tank mounted below said saw and said water jet for receiving residue, said tank including a support grating on which said material is placed.
 6. The apparatus according to claim 2, wherein the CNC receives electronic templates of parts to be cut and assigns various cuts to said saw and said water jet.
 7. The apparatus according to claim 1, wherein said saw is stopped by said CNC before the end of a straight cut to prevent overtravel.
 8. The apparatus according to claim 7, wherein said waterjet finishes said straight cut.
 9. The apparatus according to claim 1, wherein said material is supported by a grating which passes water and residue without fouling a blade of said saw.
 10. A method for cutting hard material, comprising the steps of: providing a saw and a water jet on a movable support over said hard material; introducing an electric template of desired parts to be cut from said material; controlling said saw and said water jet to move and cut said hard material under control of said CNC.
 11. A method according to claim 10, wherein the CNC assigns cuts to said saw and water jet so as to maximize efficiency.
 12. A method according to claim 11, wherein the saw is stopped before the end of a straight cut to prevent overtravel and said water jet finishes said straight cut.
 13. A method according to claim 10, wherein the CNC optimizes machine motion to minimize maintenance, consumables, and operating time of the water jet. 